On Jan 15, 2008, at 5:54 PM, Brendan Gregg wrote: > G'Day Folks, > > I'm testing out the prototype NFSv3 DTrace provider, which is > working well so far (and for anyone who missed the news, the NFSv4 > provider was putback to Solaris Nevada last year and works great). > > One of my scripts, nfsv3snoop.d, prints filename, offset and size. > While reading through a file remotely (using cksum), it traced the > following: > > # ./nfsv3iosnoop2.d > TIME(us) CLIENT OP OFFSET BYTES PATHNAME > 738601899 192.168.17.75 Rs 0 4096 /export/ > stuff/words > 738613529 192.168.17.75 Rd 0 4096 /export/ > stuff/words > 738614258 192.168.17.75 Rs 4 28672 /export/ > stuff/words > 738627681 192.168.17.75 Rd 4 28672 /export/ > stuff/words > 738628599 192.168.17.75 Rs 32 32768 /export/ > stuff/words > 738628683 192.168.17.75 Rd 32 32768 /export/ > stuff/words > 738629509 192.168.17.75 Rs 96 32768 /export/ > stuff/words > 738629597 192.168.17.75 Rd 96 32768 /export/ > stuff/words > 738629800 192.168.17.75 Rs 128 32768 /export/ > stuff/words > 738629886 192.168.17.75 Rd 128 32768 /export/ > stuff/words > 738630316 192.168.17.75 Rs 160 32768 /export/ > stuff/words > 738630439 192.168.17.75 Rd 160 32768 /export/ > stuff/words > 738630748 192.168.17.75 Rs 64 32768 /export/ > stuff/words > 738630945 192.168.17.75 Rd 64 32768 /export/ > stuff/words > 738632525 192.168.17.75 Rs 192 12288 /export/ > stuff/words > 738632577 192.168.17.75 Rd 192 10055 /export/ > stuff/words > ^C > > Rs == Read start, Rd == Read done. OFFSET is in Kbytes, BYTES is > in bytes. > > Note how the read requests skip the 64 Kbyte offset, and then > return to it 1.2 ms later? Is there a reason why NFSv3 would do > this? ... I can use DTrace to investigate - someone might already > know what's up.
Scheduling of the various NFS threads handling the reads? There is nothing in the NFS server that would try to do this so it is a result of other unintentional interactions. :-) Spencer > > This is on a single CPU server, and is repeatable. > > Brendan > > > This message posted from opensolaris.org > _______________________________________________ > nfs-discuss mailing list > nfs-discuss at opensolaris.org
